Safety thread cutter for sewing machines



March 27, 1945. A. c. SILVERMAN SAFETY THREAD CUTTER FOR SEWING MACHiNES Filed Nov. 23, 1942 2 Sheets-Sheet l March 27, 1945. A. C. SILVERMAN SAFETY THREAD CUTTER FOR SEWING MACHINES 2 Sheets-Sheet 2 Filed Nov. 23, 1942 INVENTOR; flma C Jfiriwm Patented Mar. 27, 1945 FiFlCE SAFETY THREAD CUTTER FOR SEWING HINES .MAC AnnaC. Silverman, Brooklyn,

N. I Y., assignor of 1olmi;half to Milton D. Silverman, New York,

Application November 23, 1942, Serial No. 4(i6,546 Claims; (Cl. -290) This invention relates to new and useful im provements ina safety thread cutter for sewing machines.

More specifically, the invention proposes the construction of a safety thread cutter adapted to be mounted upon the pressure foot of a sewin machine or in close proximity thereto in a manner to permit the threads to be severed at the end of a sewing operation without requiring that the operator handle a pair of scissors or cutting Still further, it is proposedto characterize the thread cutter by a shield having an edge cutout and a blade supported within a groove formed in'one' face of the shield and having a portion of its cutting edge aligned with'and extended across the edge cutout for cutting threads engaged into the edge cutout.

Another object of the invention proposes to provide the shield with on the edge cutout in a manner to direct threads to be cut into the edge cutout to be engaged by the cutting edge of the blade.

v 'A' further object of this invention proposes to adjustably mount the cutting blade upon the shield in such a manner that the blade may be shifted relative to the shield to align a new sharp portion of the cutting edge of the blade with the edge cutout when the portion being used becomes dull;

"A still further object 0f this invention proposes the provision of a novel mechanical means for moving the cutting blade relative tothe shield in a'manner to change the exposed portion of the cutting edge relativeto the edge cutout. I

It is a further object of this invention to provide a safety thread cutter for sewing machines which issimple and durable and which may" be manufactured and sold at a reasonable cost.- For. further comprehension of the invention, and of the objects and advantages thereof, reference will be had to the following description andiaccompanying drawings, and to the appended claims in which the various novel features of the invention'a're more particularly set forth. -'In the accompanying drawings forming a material part of this disclosure: 1 is a perspective view of a portion of a pressure foot. of a sewing machine having a thread cu'tter'constructed in accordance with this inventionp I Fig; 2'is a perspective view ofthe shield of the thread cutter er se. 1

cutter per se. l

Fig; 13 is a perspective view of the blade of the sloping sides converging implement to accomplish the'cuttin operation. v

Fig. 4 is 'a side elevational view of a portion of a pressure foot of a sewing machine having a thread cutter constructed in accordance with a modification of this invention.

Fig. 5 is a horizontal sectional view taken on the line 5-5 of Fig. 4.

Fig. 6 is a vertical line 6-6 of Fig. 4.

Fig. 7 is a view similar to a portion of Fig. 4 but illustrating a still further modification of the invention. I i

Fig. 8 is-a vertical sectional View taken substantially on the line 88 of Fig. 7. Fig. 9 is a side elevational view similar to Fig. 4 but illustratinga still further modification of the invention.

Fig. 10 is a horizontal sectional view taken on the line ilk-I0 of Fig. 9.

Fig. 11 is a view similarto Fig. 7 but illustrat ing still another modification of the invention.

Fig. 12 is a partial horizontal sectional view taken on the line |2l2 of Fig. 11.

Fig. 13 is a vertical sectional view taken on the line l3l3 of Fig.11.

Fig. 14 is a perspective view per se' of the cutting blade used in the last modification of the invention. i

The safety thread cutter for. sewing machines, according to this invention, includes a shield Ill having an edge cutout l I with sloping sides. I 2 and I3 converging on the edge cutout I l. The shield is constructed of metal and is adapted to be mounted on the side of a pressure foot l4 of a sewing machine, as will be hereinafter described, with its edge cutout I I disposed to the rear of the pressure foot I 4.

The inner face of the shield I0 is formed with sectional view taken on the a vertical groove l5 forming spaced shoulders which are adapted to engage opposite sides of the pressure foot M for holding the shield against horizontal movement on the pressure foot. The shield I0 is further formed with an opening l6 through which a screw I1 is adapted to be passed. The screw is adapted to be engaged with a complementary opening formed in the side of the pressure foot I 4 and cooperates with thegroo've l5in holding the shield II] in position upon the pressure foot.

The inner face of the shield 10 is also formed with'a horizontal groove l8 which extends across the'vertical groove 15 and the edge cutout l I. A bladeis having a top cutting edge 20 is adapted to be disposed within the groove I 8 with a portion of its cutting edge 20 exposed at the edge cutout to cut threads engaged into the edge cutout. The

' spaced spring clips slide the blade 19 blade 19 is also formed with a horizontal slot 2 through which the screw I! is adapted to pass and which permits the blade to be shifted relative to the shield ID for aligning a new portion of its cutting edge 20 with the edge cutout H. When the screw I1 is tightened into position the blade 19 is clamped in position between the adjacent faces of the shield l and the pressure foot M.

The manner follows:

With the thread cutter mounted upon the pressure foot l4 as shown in Fig. 1 it is an easy matter to cut threads on a piece of cloth upon which a sewing operation has just been completed. It is merely necessary to take the article from beneath the pressure foot and loop the threads over the top of the shield and move them downwards. The sloping sides l2 and 13 will direct the threads into the edge cutout and against the cutting edge 20 of the blade to be cut thereby.

In the event the exposed portion of the cutting edge 20 of the cutting blade 19 becomes dull it is merely necessary to loosen the screw l'l slightly to free the cutting blade i9to be shifted horizontally relative to the edge cutout H- to align another portion of the cutting. edge 26 with. the edge cutout l I. Retight'ening the screw ll will clamp the blade in its new position.

In the modification of the invention shown in Figs. 4 to 6 the construction of the thread cutter is similar to that previously described differing merely in the shape of the shield. l0 and the cutting blade it. In. this form of the invention the shield i0 is substantially rectangular and the cutting blade I9 is rectangular. i

In other respects this form of the invention is similar to the previous forms and like reference numerals identity like parts in each of the several views.

In Figs. '7 and 8 the shield i6" is formed with of using the thread cutter is as bottom portion of the cutting blade F9 for holding it in position with a portion of its cutting edge 20 aligned with the edge cutout H. To move the cutting blade I9" relative to the shield ID" to align. sharper portions of the cutting edge 29 with the edge cutout H it is merely necessary to in the clips 22.

In other respects this form of the invention is also similar to the previous form.

In Figs. 9 and 10 provision is made for per mittin'g the cutting blade l9' to be shifted vertically relative to the shield W for permit ing the top cutting edge of the blade to be aligned with the edge e tout as the top cutting edge becomes worn away when the edge is ground to renew the cutting edge.

To accomplish this both the groove IS in the shield W and the slot H in the cutting blade IS are arranged vertically so that the blade will be slid vertically in the loosened position of the screw H.

1 In other respects this form of the invention is also similar'to the previous form.

In Figs. 11 to 14 another modification oi the invention is shown which is characterized by a shield so having an edge cutout 3| from which 'onverging sloping sides 32 and 33 extend for directing threads into the edge cutout. The shield 39 is adapted to be mounted upon the side of a pressure foot 34 of a sewing machine with its edge cutout 3| directed to the rear thereof.

The inner face of the shield is formed with 22 which engage over the a horizontal groove 35 within which a blade slide 36 is disposed. A cutting blade 31 is mounted upon the top edge of the blade slide 36 by means of rivets 38. The cutting blade 3'! is mounted upon the blade slide 36 in such a manner that a portion of its cutting edge 39'will extend across the edge cutout 3| to cut threads engaged into the edge cutout.

Mechanical means is provided for permitting the blade slide 36 to be shifted relative to the shield 30 to align a fresh portion of the cutting edge 39 of the cutting blade 31 with the edge cutout 3|. This means is characterized by a bushing 40 rotatively extended through an opening 4| formed in the shield 30. The outer end of the bushing 40 is formed with an enlarged knob 42 by which the bushing 40 may be conveniently turned. The inner end of the bushing 40 is formed with a small pinion 43 disposed within a horizontal elongated slot 44 formed in the slide 36. The pinion 43 meshes with rack teeth 45 formed along the bottom edge of the slot 44. Thus by turning the knob 42 which in turn turns the bushing 40 and the pinion 43 the blade slide 36 may be moved to the right or the left to similarly move the blade 31 and align a new portion of its cutting edge 39 with, the edge cutout 3i.

Means is provided for mounting the shield 3!) upon the side of the pressure foot 3.4 and for locking the bushing 43 against being rotated. This means comprises a screw 46 which passes through the bushing 40, the slot 44 and threadedly engages a complementary opening 4'! formed inv the side of the pressure foot 34. Tightening the screw 45 will clamp the slide against the side of the pressure foot 34 and hold the bushing 40 against moving to hold the blade slide 36 in its various adjusted positions relative to said slide.

While I have illustrated and described the pre ferred embodiments of my invention, it is to be understood that I do not limit myself to the precise constructions herein disclosed and the right is reserved to all changes and modifications coming within the scope of the invention as defined in the appended claims.

Having thus described my invention, what I claim as new, and desire to secure by United States Letters Patent: is.

1. A safety thread cutter for sewing machines, comprising a shield having an edge cutout formed with sloping sides, means for attaching said shield on a pressure foot of a sewing machine or other part, a groove on the back of said shield and extending across said edge cutout, and. a blade adjustably supported in said groove and extending across said edge cutout.

2. A safety thread cutter, comprising a shield having an edge cutout formed with sloping sides, means for attaching said shield on a fixed support, a groove on the back of said shield and extending across said edge cutout, and a blade adjustably supported in said groove and extending across said edge cutout, said means, comprising, a screw engaged through said shield and engaging a complementary opening in said support.

3. A safety thread cutter, comprising a. shield having an edge cutout formed with sloping sides, means for attaching said shield on a fixed support, a groove on the back of said shield and extending across said edge cutout, and a blade adjustably supported in said groove and extending across said edge cutout, said means, comprising, a screw engaged through said shield and engaging a complementary opening in said support, said shield being formed with a vertical groove forming spaced shoulders for engaging the sides of said support to hold said shield against turning relative to said support about said screw.

'4. A safety thread cutter for sewing machines, comprising a shield having an edge cutout formed with sloping sides, means for attaching said shield on a pressure foot of a sewing machine or other part, a groove on the back of said shield and extending across said'edge' cutout, and a blade adjustably supported in said groove and extending across said edge cutout, said blade having a portion of its cutting edge extended across said edge cutout.

5. A safety thread cutter for sewing machines, comprising a shield having an edge cutout formed with sloping sides, means for attaching said shield on a pressure foot of a sewing machine or other part, a groove on the back of said shield and extending across said edge cutout, and a blade adjustably supported in said groove and extending across said edge cutout, said blade being adjustable horizontally to have new areas of its cutting edge aligned with said edge cutout when the area being used becomes dull.

6. A safety thread cutter for sewing machines, comprising a shield having an edge cutout formed with sloping sides, means for attaching said shield on a pressure foot of a sewing machine or other part, a groove on the back of said shield and extending across said edge cutout, and a blade adjustably supported in said groove and extending across said edge cutout, said blade being ad justable vertically to permit its top cutting edge to be aligned with said edge cutout as said top edge is worn away when the blade is ground to renew said cutting edge.

7. A safety thread cutter for sewing machines, I

edge cutout for attaching a sewing macomprising a shield having an fromed with sloping sides, means said shield on a pressure foot of part, a groove on the back of said shield and extending across said edge cutout, and a blade adjustably supported in said groove and extending across said edge cutout, said blade being mounted upon a blade slide, and means for moving said blade slide relative to said shield to align new areas of said cutting blade with said edge cutout.

9. A safety thread cutter for sewing machines, comprising a shield having an edge cutout formed with sloping sides, means for attaching said shield on a pressure foot of a sewing machine or other part, a groove on the back of said shield and extending across said edge cutout, and a blade adjustably supported in said groove and extending across said edge cutout, said blade being mounted upon a blade slide, and means for moving said blade slide relative to said shield to align new areas of said cutting blade with said edge cutout, said latter means, comprising a turnable bushing formed with a small pinion disposed with a slot formed in said blade slide and meshing with teeth formed along ,the bottom edge of said slot,

10. A safety thread cutter for sewing machines, comprising a shield having an edge cutout formed with sloping sides, means for attaching said shield on a pressure foot of a sewing machine or other part, a blade positioned behind said shield with an area of its cutting edge extending across said edge cutout, and means supporting said blade on said shield to be shiftable relative to said shield to vary the aligned position of the cutting edge with said edge cutout.

ANNA C. SILVERMAN. 

